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/*
* elfupdate.c - create/update psdatabase for ELF kernels.
*
* Copyright (c) 1995, 1996 Jeffrey A. Uphoff <juphoff@nrao.edu>
*
* This file is based (loosly) on the following:
* ------------------------------------------------------------------
* update_db.c - create/update psdatabase
*
* Copyright (c) 1992 Branko Lankester
*
* munged into psupdate.c by Michael K. Johnson for the procps suite.
* ------------------------------------------------------------------
*
* (All of the ELF-specific code is new.)
*/
#include "psupdate.h"
#ifdef ELF_CAPABLE
#define ELF_OBJECT 1
#define ELF_FUNC 2
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <fcntl.h>
#include <elf.h>
extern unsigned long k_addr (char *);
static Elf32_Ehdr E_hdr;
static Elf32_Sym *E_sym;
extern char *strings;
extern long nsym, stringsize;
int
check_elf_magic (int fd, const char *systemfile)
{
MLSEEK (fd, 0, SEEK_SET, systemfile);
MREAD (fd, &E_hdr, sizeof (E_hdr), systemfile);
return strncmp (&E_hdr.e_ident[EI_MAG0], ELFMAG, SELFMAG);
}
/*
* This whole thing could probably be rewritten to use libbfd.
*/
int
read_elf_nlist (int fd, const char *systemfile)
{
Elf32_Shdr E_shdr[2];
int i;
#ifdef DEBUG
int j;
#endif
/* Go to the section header table. */
MLSEEK (fd, E_hdr.e_shoff, SEEK_SET, systemfile);
/*
* Find the symbol table entry. There can be only one. (Thanks
* Highlander.)
*/
for (i = 0; i < E_hdr.e_shnum; i++) {
MREAD (fd, &E_shdr[0], sizeof (Elf32_Shdr), systemfile);
if (E_shdr[0].sh_type == SHT_SYMTAB)
break;
}
if (i == E_hdr.e_shnum) { /* Uh, oh. */
fprintf (stderr, "%s:\n"
"No symbol table entry in section header table! (Stripped kernel?)\n",
systemfile);
exit (1);
}
/* We found it. Now go to string table entry. */
MLSEEK (fd, E_hdr.e_shoff + E_shdr[0].sh_link * sizeof (Elf32_Shdr), SEEK_SET,
systemfile);
MREAD (fd, &E_shdr[1], sizeof (Elf32_Shdr), systemfile);
assert (E_shdr[1].sh_type == SHT_STRTAB); /* Sanity! */
strings = (char *)xmalloc (stringsize = E_shdr[1].sh_size);
/* Go to the string table. */
MLSEEK (fd, E_shdr[1].sh_offset, SEEK_SET, systemfile);
/* Slurp it in. */
MREAD (fd, strings, E_shdr[1].sh_size, systemfile);
E_sym = (Elf32_Sym *) xmalloc (E_shdr[0].sh_size);
/* Go to the symbol table. I like to do things backwards in July. */
MLSEEK (fd, E_shdr[0].sh_offset, SEEK_SET, systemfile);
nsym = 0;
#ifdef DEBUG
j = 0;
#endif
for (i = 0; i < (E_shdr[0].sh_size / E_shdr[0].sh_entsize); i++) {
MREAD (fd, &E_sym[i], E_shdr[0].sh_entsize, systemfile);
#ifdef DEBUG
if (E_sym[i].st_name != 0 && ELF32_ST_TYPE (E_sym[i].st_info) != STT_FILE)
++j;
#endif
}
nsym = --i;
#ifdef DEBUG
fprintf (stderr, "read %d symbols (%d total) from %s\n", j, nsym, systemfile);
#endif
return (0);
}
/*
* ELF is nice; it's easier to use one relatively generic function for
* making both the function and variable tables.
*/
struct sym_s *
make_elf_tbl (struct sym_s *p, int vartable)
{
int i, type;
type = vartable ? ELF_OBJECT : ELF_FUNC;
/*
* This is not really needed; it's here as a sanity check. If the
* values for various ELF internals are changed, we'll have other
* (bigger) problems most likely. Still, it's here for cleanliness: I
* need to do this for now to keep all ELF-specific stuff out of
* psupdate.c.
*/
assert (type == ELF_OBJECT || type == ELF_FUNC);
type = (type == ELF_OBJECT) ? STT_OBJECT : STT_FUNC;
for (i = 0; i < nsym; ++i)
if (ELF32_ST_TYPE (E_sym[i].st_info) == type) {
p->addr = E_sym[i].st_value;
p->name = E_sym[i].st_name;
++p;
}
return p;
}
void
read_elf_uts (int fd, struct new_utsname * uts, const char *syspath)
{
/*
* Simply seeking to k_addr ("sym") works fine when offset properly
* (at least I've yet to see it fail on a kernel image).
*/
MLSEEK (fd, k_addr ("system_utsname") - E_hdr.e_entry, SEEK_SET, "lseek");
MREAD (fd, uts, sizeof (*uts), syspath);
}
#endif /* ELF_CAPABLE */
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